Inflatable boat



Jan. 1, 1,946. c, KEARNY 2,391,906

INFLATABLE BOAT Filed Oct. 24, 1941 Cre sson H. Hear/n3 Patented Jan. 1, 1946 UNITED STATES. PATENT- OFFICE INFLATABLE BOAT Cresson H. Kearny, United States Army Application October 24, 1941, Serial No. 416,329

15 Claims.

(Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) This invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to me of any royalty thereon.

This invention relates to an inflatable boat of the type which can be transported easily and prepared for use without undue delay. More particularly, it refers to an inflatable boat which can be inflated quickly by a low pressure means such as the human breath and which utilizes trapped water as a stabilizing means. Because of its light weight and rapid assembly, my boat is especially adapted for military use but is equally serviceable to hunters, fishermen, explorers, pleasure-seekers, or, in short, to any one desiring a small pneumatic water transport. s

It is well known to use pneumatic members for obtaining extreme buoyancy in water craft and to provide these pneumatic members with strengthening attachments and with load supporting attachments. It is also well known to stabilize inflatable floating apparatus by means of ballast weights. By my invention, I provide a small pneumatic boat which is extremely rigid without the necessity of using auxiliary bracing for the pneumatic members and which is extremely stable without the necessity of using special ballast weights. Moreover, I do not sacrifice lightness, portability, r ease of assembly to attain these advantages.

It is, accordingly, an object of the present invention to provide an inflatable boat which contains a plurality of wide-aperture, low-pressure valves whereby the boat can be readily inflated by means of the human breath.

Another object is to provide an inflatable boat which is stabilized by water trapped in the bottom portion of the boat as well as by a partial vacuum action in a space above the trapped Water on the up-tilted side of the boat.

Another object is to provide an inflatable boat in which stress concentrations are distributed because of the multi-compartment design and in which the tendency to buckle is lessened because water pressure is exerted against the wall surrounding the opening in a substantially doughnut-shape buoyant member and directly against the load container as well as against the outside wall of the buoyant member.

Other objects and advantages of my invention will become apparent from the following detailed description and the attached drawing and the invention will be pointed out with particularity in the appended claims. In the drawing:

Fig. 1 is a plan view of my boat with the boat bottom and inner-sheet removed;

Fig. 2 is a sectional view on lines 2-2 of Fig. l with the boat bottom and inner-sheet shown;

Fig. 3 is a plan view of the boat bottom; and

F 4 is a sectional view, along the longitudinal axis, of a wide-aperture, low-pressure valve which I use in my boat.

Referring to 'Fig. 1, I indicates the housing for the pneumatic members which is approximately toroidal or doughnut-shaped and which is formed from a plurality of compartments or segments :2, seven such segments being provided in the embodiment shown. The walls of the; housing I may be made of ordinary, tight woven shirt'cloth, or any such suitable material; The individualair compartments or segments 2 are sewed together and provided with cloth partitions 3 sewed to-the inner side of the seam line between the compartments 2. With the partitions 3 in position, seven individual air compartments 2 are formed which have a teardrop cross-section, as illustrated in Fig. 2. Each air compartment 2 contains a bladder 4 in the form of a rubber balloon, preferably of the type ordinarily used by the Signal Corps of the United States Army, although other materials may be used for constructing the bladder as lon as the material used is deformable and has properties insuring a high resistance to the deteriorating action of salt water. By means of valves 5. these individual balloon-bladders 4 may be inflated or deflated, and when inflated conform closely to the shape of the air compartment 2.

Valves 5 are illustrated in detail in Fig. l. As

" shown there, each valve is made'up of a body member '6, a plug member 1, a valve stem 8. and a plurality of resilient bands 8 and l 0 for holdin the various component parts in assembled relation. Body member 6 is a hollow tubular member, flared at the bottom, and may be made of glass. An ordinary glass bottleneck will serve satisfactorily. Plug 1 bears against the sloping interior wall of member 6 to effectively prevent the escape of air from bladder 4. I construct plug 1 by filling a bulb of doubled toy balloon rubber with a low freezing point liquid I I such as glycerine. A valve stem 8 extends into the interior of valve plug 1 and proiects above the mouth of member 6. Resilient bands 9, such as ordinary thin rubber bands. extend around opposite ends of plug 1 to seal the liquid I l therein. Where stem 8 enters plug I, bands 9 compress the rubber sides of the opening in plug 1 tightly against the valve stem. At this same location, bands 9 also secure one end of a plurality of thin rubber bands In which are stretched from the interior of the valve, over the edge of the mouth of member. 6 to beneath the bead I2 on member 6 Where they are again secured by another set of bands 9.

Since the bands II] are in tension, they exert a force on plug 1 tending to wedge it agaimt the inside sloping wall of member 6. This force is sufiicient to wedge plug I tightlyenough to prevent the escape 'of air from bladder 4 but it can be overcome by the force of the human breath. Because the aperture in member 8 is comparatively wide, a person can empty his lungs into bladder 4 almost as fast as he can breathe. Similarly, bladder 4 can be deflated in a veryfewseconds merely by pressing down upon valve stem '8. The valves are held in position for instant use by being attached with resilient members, suchas ordinary rubber bands, to tabs I3 fixed to the walls of the air compartments 2.

The lift of the balloon-bladders4 istransmitted to the load of the boat through a flange I4, which may be made of doubled-heavy canvas, attached to the continuation of theteardrop cross-section ridge of the cloth compartments 2. Across the bottom of the cylindrical flange I4 is seweda flat light-canvas bottom I5, shown more completely in 'Fig. 3. The canvas member I5 gives the boat a smooth bottom and acts to trap the water ballast as described more fully hereafter. Small strips 'of canvas are stitched to the upperside-of the boat to the cylindrical 'flange I'4, and-are-tiedin placgbycords which in turn are tiedto the cylindrical flange '-I4. If desired, -'the boat may be used without placing-strengthening members It in'the tubes IS.

The load of the boat -is-carrie'd dry in a"bucket like depression made by placing a waterproof sheetI8,preferablywaterproofed canvas,-over the walls oI-the pneumatic member housing I. This separate sheet I9 can be used as'a tent-fly'or as a shelter-half for a tent since it is not necessary to stitch it or otherwise attach'it to the rest'of the boat. Thus, it-will'be seen that the sheet I9 need not be 'Of any special shape as long as it fits over the-sides of the pneumatic housing I, althoughif desired, a special canvas bucket could be provided for carryingthe'load which would work as satisfactorily assheet I9 aslong as it was waterproof.

When it is desired to use 'the'boat, the indi-' -v1dual bladders 4 are inflated causing th housing I to assume its generally toroidal or doughnut shape. Strengthening rods or sticks I6 mayor may not be inserted into the tubes I5 depending upon the'user"s desire. Then the boat, less the load containinginner sheet I3, is placed into'the water which begins to leak slowly through small openings orports in thebottom 55,. and through those ,portions of openings I! which are not blocked by the strengthening members It pro.- .Jecting from tubes .I6,, until the average water levelin the interior of the boatjs .the same .as the average outside water level. Meanwhile, theload containing inner sheet J9 ,is placed .across the I' QP .Of the boat where .it ,rests upon the .upper surface of the housing .I to form :a loose airseal.

Sheet I.9.is depressedinthecehtertoforma space in positionlbeforeithezboat is-put into the water.

When the boat, assembled and loaded, is floating in the water, the water which has leaked in through openings or ports 20 in the bottom I5, and through the unblocked portions, if any, of the openings I! in flange I4, is confined in a space 2| bounded by the bottom I5, the interior side of the housing I for the pneumatic members, the side forming the opening in the doughnut shape, and the inner sheet I9. The amount of water confined in this space will depend upon the displace- .ment or, in other words, upon the load contained in inner sheet I9. This trapp d Water acts as a stabilizing medium for the boat since it has an appreciable weight and inertia. The inertia of the trapped water adds to the inertia of the rest of the boat to oppose sudden movement in a horizontal direction. A change in a vertical direction, 'such as tilting, is resisted by the weight and inertia of the water .on the uplifted side. This 0c- .curs'because the openings 20 in bottom I5, and the unblocked portions, if any, of openings I I in flange I 4, are so small that the water can escape but slowly from space 2| on the upraised side and consequently the trapped water-ballast .is lifted above the outside water level on the uptipped side where it acts as a weight to right the boat. An added stabilizing effect is obtained from atmospheric pressure exerted upon the uptilted side. When one side of the boat is raised, the water level in space 2| on that side drops, somewhat tending to create a partial vacuum above the water because passage of air through the space between pneumatic housing I and inner sheet I9 is restricted by the loose air seal produced by sheet I9. Because of this vacuum action the water in space 2 I, on the uptipped side, is'raised above the outside water level even when the boatis without the'canvas bottom'l 5. Sinc the sealing action of inner sheet I9 .is not 'perfect,'a partial vacuum in "a portion'of space 2| will not last indefinitely, but it does last long enough to-produce an immediate "added stabilizing 'gefi'ect. Similarly, the water trapped in the .upraised portion of space "2 I will leak out ultimately, but for a-short interval -it exerts a force, due tozits weight and inertia, whlch tends to oppose a :change in its position. The combined result of the vacuumaction plus the water-ballast trapping andliftin by the canvas bottom I5 results in efiicient-stabilizing of the boat. From the above description, it willbe-seenthat I have invented a boat which is extremely simple .to build, light 'in weight and easy to assemble, and one which'is'rlgid and stable when .in operation. The boat is constructed of materials which are easy to obtain and acertain amountof flexibility in the choice of materials isallowed. When the parts are assembled, they can be folded and packed into ra small bundle which weighs less than ten pounds. 'This bundle can be fitted into a soldier's pack, where 'one component .of the boat, the tent shelter half which can be -used as the waterproof inner sheetI 9, is normally carried. .After the site'of use is reached, the boat can be preparedfor use quickly because of. the easy inflating action of the valves .in .the .individual bladders. Similarly, it can .be .quicklydedated and repacked after use. .If it is desired .to use strengthening members for the bottom .I5, im-provisedmeans such as the branchesiof .small trees in the vicinity, -or .anyequally applicable locally-cut sticks can be used, .as dong as the means used will fit into-the tubes .I B. Since water pressure is exerted against the interiorside of .the toroidally or doughnut-shaped pneumatic housing, the side adjacent to the interior of the boat, and against the bulkof the load in the load containing inner sheet as well as against the exterior side of the pneumatic housing, there is less tendency for the boat to buckle in the center and internal cross-bracing can be dispensed with. The multicompartment design, using a plurality of individual bladders, insures a distribution of the lifting effort and minimizes the danger of sinking since the failure of an individual bladder does not remove the entire lifting efiort. Should one of the bladders:

fail when the boat is in use, a spare bladder can be inserted without much difliculty. The toroidal, multicomparment design having a teardrop cross section with a strengthening flange and bottom attached thereto provides a structure strong in relation to its weight, one which greatly reduces stress concentrations at any particular point, and one which is capable of carrying at least two persons of average weight with safety.

Furthermore, the addition of a simple water-.

proofed sheet, which need not be attached or fastened to the rest of the boat, but instead is merely laid across the upper surface of the boat and depressed in the center, furnishes a comparatively dry load container and also completes a space for trapping water which results in an eflicient stabilizing action without added weight as previously explained.

While I have described and illustrated a particular embodiment of my invention, it is to be as new and wish to secure by Letters Patent is: l. A boat comprising a buoyant member'provided with a central opening, a bottom member attached to said buoyant member, said bottom member having restricted water passage openings therein, and a flexible water-proof load inclosure member placed across the upper surface of the buoyant member and depressed into the opening in the buoyant member so that a portion of said flexible member rests against the bottom and is below the level of the water admitted by said restricted water passage openings.

2. A boat comprising a buoyant member provided with a central opening, a boat bottom attached to the buoyant member and having restricted openings therein, and a flexible member placed across the upper surface of the buoyant member and adapted to overlie said upper surface to produce an air seal between this surface and the flexible member, said flexible member being depressed into the opening in the buoyant member to form a load inclosure and to complete a trapped water space bounded by the flexible member, the buoyant member and the boat bottom, said restricted openings in the boat bottom affording a controlled liquid flow to and from the trapped water space.

3. A boat comprising a buoyant member provided with a central opening, a boat bottom attached to the underside of the buoyant member, a flexible waterproof sheet placed across the upper surface of the buoyant member and depressed into the opening in said member until it rests against the boat bottom, said flexible sheet pro- .4.v A knockdown boat comprising a plurality of inflatable buoyant elements, a substantially doughnut shaped housing for said elements, a boat bottom attached to a continuation of said housing, a' flexible waterproof sheet placed across the upper surface of the housing for the inflatable buoyant elements and adapted to overlie said upper surface to produce an air seal between this surface and the flexible sheet, said flexible sheet being depressed into the opening in the housing for the buoyant elements to form a load inclsoure and to complete a space bounded by the flexible sheet, the housing for the buoyant elements and the boat bottom, and a plurality of restricted openings in the boat bottom which permit liquid to enter said space to act as a stabilizing means for the boat.

5. A knockdown inflatable boat comprising a plurality of inflatable elements individually housed in a multicompartment housing ofsubstantially doughnut shape, a boat bottom attached to a continuation of said housing, a flexible member placed across the upper surface of said housing and overlying said housing to form a loose air seal between the housing and the flexible member, said flexible member being depressed into the opening in said substantially doughnutshaped housing to form a load inclosure and to complete a space bounded by the flexible member, the multicompartment housing, and the boat bottom, and means for stabilizing the boat, said means including water trapped in the space bounded by the flexible member, the multicom- .partment housing; and the boat bottom.

6. A pneumatic boat comprising a plurality of inflatable elements, a substantially doughnutshaped housing for the inflatable elements, a boat bottom attached to said housing, a waterproof sheet placed across the upper surface of said housing to form a loose air seal between this surface and the sheet, said sheet being depressed into the opening in the substantially doughnutshaped housing until the sheet rests against the upper surface of the boat bottom and completes a space bounded by the sheet, the boat bottom, and the inflatable element housing, and a plurality of restricted ports in the boat bottom which allow liquid to slowly enter or leave said space, whereby the boat is stabilized by the weight of liquid trapped in said space and by a force opposing the force exerted by the air trapped above the water 'in said space.

'7. In a boat, a bottom comprising a substantially flat bottom member, and a plurality of strips attached to a surface of said member to form tubes, reinforcing members removably mounted in said tubes, at least one of said strips being placed at an angle to the others and means for securing said reinforcing members in place in said strips. I

8. In a boat, a substantially flat bottom, a plurality of strips attached to said bottom to form tubes, readily removable bottom reinforcing members in said tubes, 3, flange attached to said bottom and having openings therein, said openings in said flange adapted to receive the bottom reinforcing members and means mounted on said flange for securing said reinforcing members in place in said strips.

9. A .boat including a plurality of inflatable elements individually housed in a multi-compartment housing of substantially doughnut shape, said individual compartments being of approximately equal size and symmetrically disposed about the center of the boat, and said housing having :depending lzsubstmrtially avertical :extensions therefrom, a substantially werti'call'fiange zmemberzsupported between said extensions, and 1a :boet bottom attached tosaidulange member.

1.0.. in an inflatable boat, an inflatable anem- -ber forming :a part of the boat and Enaving :an :inflation rand :deflation opening, a housing for :said inflatable member, said housing having an openingftherem inalinementwvith the :opening in therinflatable member, aipluralityof tabsadja- :centzthe :openingin said housing, a'wi'de aperture .-10W?D1CSS111'6 valve extending through :both the :openingfin .therinflatable member anrlthe opening in :the housing :therefor, said valve comprising :a body member having :a :liquid filled valve stop mounted :therein, and a plurality. of resilient members engaging the tabs adjacent the opening in the :housing for the inflatable member and :smzrounding said valve tohold it in position.

III. :In a :boat, on inflatable i-member forming :a partrof the boat and having *an opening therein, -a 'bottle-neckshaped wide-aperture low-pressure valve member :located in :said opening, :said valve memberaengaging-the sides of 1the opening in said --infln.table :member to cause the portions of the inflatable member adjacent :said opening to conform to the shape of the exterior of said valve member, valve memberdiaving a liquid-filled valve stop mounted therein, a plurality of :tabs ilooated adjacent the opening "in said inflatable member and :a plurality of resilient members zenlgaging :said tabs and said valve member to hold tbeilaltter miposition.

12. In about, an inflatable member forming a part of the boat and having :an opening therein, s. rhonsing for :said inflatable anember, said hous- 11m having an opening therein in :alinement with the opening. in the inflatable member, 'a plurality :of atdbs adjacent the opening in :said housing, a

' 'valvwezextendingthroughibothnpenings, ssaid waive comprising a-ibodyzm'ember having a low freezing pointliquid-fllled:valvestopmounted therein, and a. plurality. of resilient members engaging the tabs adjacent the opening in-the housing .for the inflatable member and also engaging the valve member 2130 hold the latter in position.

23. In an inflatable boat, a plurality of buoyant elements and a housing therefor, an extension formed .on said housing and having openings therein, a substantially flat bottom attached to .said :extension :and reinforcing members removably-mounted on said bottom, said reinforcing membersadapted to-extendzthrough the openings in said :extension.

14. Juan inflatable boat, a;plura1ity of :pneumatic supporting members, individual housings mounted :on :said bottom, said reinforcing-members adapted to extend through the openings in said flange.

15. In aninfiata-ble boat, 'a plurality of pneumatic supporting members and a housing therefor, :an extension :formed on said housing and having restricted openings therein, a substantially flat bottom attached to said extension and .havingrestricted openings therein and reinforcing members removably mounted-on said bottom, said reinforcing members adapted to extend through the openings insaid flange and said restricted openings affording a controlled water flow through said bottom.

CRESSON H. 

